As a machining object, there is one having a stem portion and an expanded diameter portion which is integrated with one end side of the stem portion, so as to expand its diameter larger than the stem portion. Such a machining object is, as shown in Patent Document 1, usually, chamfered at the other end rim portion of the stem portion by use of a turning tool for chamfering in a chamfering process in a process line.
Meanwhile, the above-described machining object is required to be finally a constant length as the entire length according to its type. Therefore, a cutting process is provided in the machining line (process line), and in the cutting process, the stem portion of the machining object is cut to be a predetermined length in order to cut the entire length be the constant length. In this case, in the cutting process, a burr is generated on a cut end face rim portion of the stem portion of the machining object. However, this burr is eliminated in accordance with grinding of the stem portion by use of a rubbing stone in the following grinding process. Therefore, it is possible to eliminate the burr from the cut end face rim portion of the stem portion even though a specific process is not provided for deburring, thereby it is possible to prevent an increase in length of the machining line (manufacturing line) for deburring.